Alignment method and exposure apparatus using the method

ABSTRACT

A method for aligning existing layers formed prior to a new layer and the new layer in forming the new layer on a wafer  4 , wherein a microscope  6  as a first measurement condition and a microscope  7  as a second measurement condition are used, and marks  4   a  and  4   b  formed in each of said existing layers are measured by switching the first and second conditions, and said existing layers and said new-layer are aligned based on measurement of mark position of each of said existing layers, and the microscope  7  has a plurality of measurement conditions as optical characteristics, and the measurement conditions are switched.

This application is a divisional application of U.S. patent applicationSer. No. 09/946,486, filed Sep. 6, 2001, now U.S. Pat. No. 6,838,686,issued on Jan. 4, 2005.

FIELD OF THE INVENTION

The present invention relates to an alignment method and an exposureapparatus using the method, and particularly is suitable for analignment method in semiconductor manufacturing and method andapparatuses for manufacturing devices using it.

BACKGROUND OF THE INVENTION

Currently, in semiconductor manufacturing, a semiconductor device isfabricated by depositing multiple layers successively. In actualsemiconductor manufacturing, a method is known wherein instead ofmeasuring positions of alignment marks formed in a layer prior toexposure, marks are formed in the multiple layers and alignment isperformed by measuring positions of the marks in multiple layers.

As described in Japanese Patent Laid-Open No. 7-321012, it is suggestedthat when forming a layer on a substrate, the layer is formed aftermeasuring positions of marks formed in each of at least two layersformed prior to the layer, based on measurement of the mark positions ineach of said layers.

In the past, there has been a problem that, in measuring alignment marksformed in each layer, the measurement accuracy is degraded due tomanufacturing processes such as the physical feature and resistapplication condition of each alignment mark.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an alignment methodand an exposure apparatus using the method wherein high accuracyalignment is provided by switching measurement conditions or measurementparts for the alignment in measuring alignment marks formed in eachlayer.

In order to achieve the object above-described, an alignment method ofthe present invention is a method wherein when forming a new layer on asubstrate, alignment is performed by measuring each position of existinglayers formed prior to the above-described new layer and theabove-described new layer in a first measurement condition or a secondmeasurement condition, comprising the steps of: measuring by switchingbetween the above-described first and second measurement conditions formarks formed in each of the above-described existing layers; andperforming alignment between the above-described existing layers and theabove-described new layer based on measurement of mark positions of theabove-described existing layers.

Preferably, the above-described second measurement condition has aplurality of different conditions in an optical characteristic, and themeasurement is performing by switching the measurement conditions. Asthe optical characteristic, preferably wavelength of illumination lightfor the measurement is switched. As the above-described opticalcharacteristic values representing light intensity distribution ofillumination light for the measurement (σ=standard deviation) may beswitched.

The present invention includes an exposure apparatus for using any ofthe above-described alignment method and forming the above-described newlayer.

The exposure apparatus according to the present invention is anapparatus wherein an exposed object is aligned based on measurement ofposition information on marks formed in each of existing layers on theexposed object on which the existing layers are provided and a new layeris to be formed, and then projection exposure is performed, theapparatus having a first measurement part and a second measurement partfor measuring the position information on the marks, the above-describedfirst and second measurement parts being configured such that they canbe switched for the marks formed in each of the above-described existinglayers.

It is preferred that the above-described first and second measurementparts are switched manually, or that switching of the above-describedfirst and second measurement parts are performed based on automaticcalculation of contrast that is made before exposure.

An exposure method of the present invention is a method for aligning anexposed object having a plurality of existing layers with alignmentmarks formed in each of them based on measurement of the alignmentmarks, and projection-exposing the object, wherein when measuring thealignment marks in the above-described each layer, each alignment markis measured by switching conditions of illumination light for themeasurement depending on the particular alignment mark in each layer.

The present invention can also be applied to a semiconductor devicemanufacturing method comprising the steps of: installing in asemiconductor manufacturing factory a plurality of manufacturingapparatuses for performing various processes including theabove-described exposure apparatus; and manufacturing semiconductordevices by performing a plurality of processes with the manufacturingapparatuses. The semiconductor device manufacturing method may be alsocharacterized in that it further comprises the steps of: connecting theabove-described manufacturing apparatuses by a local area network; anddata-communicating information about at least the above-describedmanufacturing apparatuses of the above-described manufacturingapparatuses between the above-described local area network and anexternal network outside the above-described semiconductor manufacturingfactory, characterized in that maintenance information for theabove-described exposure apparatus is obtained by accessing andcommunicating data with a database provided by a vendor or user of theabove-described exposure apparatus via the above-described externalnetwork, or production control is conducted by communicating data viathe above-described external network between the above-describedsemiconductor manufacturing factory and a semiconductor manufacturingfactory other than the above-described semiconductor manufacturingfactory.

The present invention may be applied to a semiconductor manufacturingfactory comprising: a group of manufacturing apparatuses for performingvarious processes including the above-described exposure apparatuses; alocal area network for connecting the manufacturing apparatuses; and agateway allowing access by the local area network to an external networkoutside of the factory, wherein data communication of information aboutat least one apparatus of the above-described manufacturing apparatusesis provided, and the present invention can be applied to a maintenancemethod for an exposure apparatus installed in a semiconductormanufacturing factory, comprising the steps of: a user or vendor of theabove-described exposure apparatus providing a maintenance databaseconnected to an external network for the semiconductor manufacturingfactory; allowing access from inside of the above-describedsemiconductor manufacturing factory via the above-described externalnetwork to the above-described maintenance database; and transmittingmaintenance information stored in the above-described maintenancedatabase via the above-described external network to the semiconductormanufacturing factory side.

The present invention may also be characterized in that theabove-described exposure apparatus further comprises a display, anetwork interface, and a computer for executing software for thenetwork, wherein data-communication of maintenance information on theexposure apparatus via a computer network is provided, and preferably,the software for the network provides on the above-described display auser interface connected to an external network for a factory with theabove-described exposure apparatus installed therein, for accessing amaintenance database provided by a vendor or user of the above-describedexposure apparatus, whereby allowing acquisition of information from thedatabase via the above-described external network.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a block diagram showing an exposure apparatus comprising analignment device including a non-exposure TTL mechanism and an Off-Axismechanism according to an embodiment of the invention;

FIG. 2A is a plan view of an in-shot arrangement for alignment marksaccording to an embodiment of the present invention;

FIG. 2B shows a step formation for the alignment marks;

FIG. 3 shows measurement shots in global alignment according to anembodiment of the present invention;

FIG. 4 shows a measurement/exposure sequence according to an embodimentof the present invention;

FIG. 5 is a flowchart showing a procedure for determining an optimizedmeasurement condition for each mark;

FIG. 6A shows an alignment mark image and a process window;

FIG. 6B shows a one-dimensional digital signal sequence, to which atwo-dimensional image signal is converted, obtained by setting thealignment mark image and the process window;

FIG. 7A shows an image signal with high contrast;

FIG. 7B shows an image signal with low contrast;

FIG. 8 shows a conceptual view seen from one angle of a productionsystem for semiconductor devices using an apparatus according to thepresent invention;

FIG. 9 shows a conceptional view seen from another angle of a productionsystem for semiconductor devices using an apparatus according to thepresent invention;

FIG. 10 shows a specific example fo a user interface;

FIG. 11 shows a process flow for manufacturing devices; and

FIG. 12 illustrates a wafer process.

Other objects and advantages besides those discussed above shall beapparent to those skilled in the art from the description of a preferredembodiment of the invention which follows. In the description, referenceis made to the accompanying drawings, which form a part thereof, andwhich illustrate an example of the invention. Such an example, however,is not exhaustive of the various embodiments of the invention, and,therefore, reference is made to the claims which follow the descriptionfor determining the scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An alignment method according to an embodiment of the present inventionswitches measurement conditions or measurement parts in measuringalignment marks formed in each layer.

In the past, in exposure apparatuses, as a measurement mechanism foralignment marks to obtain information about position in a wafer surface,there are known an Off-Axis mechanism wherein non-exposure light is usedand does not pass any projection lens, and a non-exposure TTL (ThroughThe Lens) mechanism wherein non-exposure light is used and passes aprojection lens.

Particularly, multiple wavelengths are recently used as illuminationlight for observation in order to improve detection accuracy for AA markobservation images. For example, the use of a light source with arelatively wide wavelength width by a halogen lamp (633±30 nm, forexample) as illumination light for observing non-exposure light ischaracterized in that an interference fringe by a resist film, whichtends to occur when observing an AA mark on a wafer by using amonochromatic light source such as a He—Ne laser, can be reduced,thereby providing better alignment.

There is also a method to improve the interference conditions by varyingthe center wavelength of illumination light.

It is also possible to vary illumination conditions for a He—Ne laser,for example, conditions for a value representing a light intensitydistribution of illumination (σ=standard deviation).

Thus, in order to support processes that vary for each layer, eachalignment mark is measured by switching conditions of illumination lightoptimized for alignment marks in each layer when measuring alignmentmarks in each layer.

Various embodiments will be now described with reference to thedrawings.

First Embodiment

FIG. 1 shows an exposure apparatus comprising an alignment deviceincluding a non-exposure TTL mechanism and an Off-Axis mechanism,according to a first embodiment of the present invention.

As shown in FIG. 1, light from a light source emitted by illuminationsystem 1 irradiates a reticle 2 as a first object. Patterns on a surfaceof the reticle 2 are projection-transferred onto wafer 4 as a secondobject by a projection optical system 3. The wafer 4 is fixed onto amovable stage 5 disposed on a base plate 10. The reticle 2 is held on areticle stage 2 a, and the reticle stage 2 a is moved in X, Y, Z, and θdirections by means of a reticle drive mechanism (not shown).

On the wafer 4, a plurality of alignment marks 4 a and 4 b have beenformed in existing layers until the last process step, which marks arelocated in a certain positional relationship with respect to circuitpatterns. Reference numeral 6 denotes a microscope with a TTL mechanismas a first measurement condition or measurement part. The TTL microscope6 is a microscope that reads the alignment mark 4 a on the wafer 4through lenses of the projection optical system 3, and performs positionmeasurement for the alignment mark 4 a on the wafer 4 by a mirror 6 dlocated between the reticle 2 and the projection optical system 3.Reference numeral 6 a denotes an illumination light source with a He—Nelaser, and reference numeral 6 b is a CCD camera. The illumination lightemitted by the illumination light source 6 a is transmitted by analignment optical system 6 c and mirror 6 d disposed between the reticle2 and projection optical system 3, through lenses in the projectionoptical system 3, thereby illumination alignment mark regions on thewafer 4.

Light reflected or scattered on the wafer 4 based on the alignment mark4 a is transmitted again through the lenses in the projection opticalsystem 3, by the mirror 6 d and alignment optical system 6 c, and thenis imaged on the CCD camera 6 b.

The CCD camera 6 b processes the image of the alignment mark 4 a toobtain position information on the wafer 4.

Reference numeral 7 denotes an Off-Axis microscope as a secondmeasurement condition or measurement part, which microscope has twomeasurement methods. It is placed at a position other than the TTL typemicroscope 6 and measures an alignment mark 4 b formed at a position ina certain positional relationship with respect to an exposed position.Reference numeral 7 a denotes a first illumination light source with aHe—Ne laser used in a first measurement method, and reference numeral 7b denotes an illumination light source with a halogen lamp used in asecond measurement method, and reference numeral 7 c denotes a CCDcamera. One of these two light sources 7 a and 7 b used in the first andsecond measurement methods is selected as a light source, andillumination light from the light source illuminates an alignment markregion on the wafer 4 through an alignment optical system 7 d withoutpassing through the projection optical system 3.

The light reflected or scattered on the surface of the wafer 4 is againimaged through the alignment optical system 7 d on the CCD camera 7 c.The position information is measured by image-processing with the CCDcamera 7 c.

FIGS. 2A and 2B show examples of arrangements of alignment marks of thisembodiment. FIG. 2A shows an in-shot plan arrangement, and FIG. 2B showsa step formation of the alignment marks. Reference numerals 11 and 13denote alignment marks formed in layer A, and reference numerals 12 and14 denote alignment marks formed in layer B.

FIG. 3 shows an example of an arrangement for measurement shots S1 to S8in global alignment, and FIG. 4 shows a measurement/exposure sequence inthe example. After selecting a reticle set at step 31, a wafer set atstep 32, and a halogen lamp as the light source at step 33, at firstusing the Off-Axis microscope 7, while halogen lamp 7 b with a widewavelength band is being set as the light source, alignment mark 11formed in layer A shown in FIGS. 2A and 2B is measured at step 34, andalignment mark 13 formed in layer A shown in FIGS. 2A and 2B is measuredat step 35. Next, after selecting He—Ne laser light as the light sourceat step 36, while the He—Ne laser light 7 a is being set as the lightsource, the alignment mark 12 formed in layer B is measured at step 37and the alignment mark 14 is measured at step 38.

A determination is made of all sample shots having been measured at step39, so that the measurements described above are repeated untilmeasurement of all sample shots is completed. Upon completion ofmeasurement of all sample shots, deviations of the reticle with respectto layer A is calculated from measurements of the mark 11 and mark 13 atstep 40, and deviations of the reticle with respect to layer B iscalculated from measurements of the mark 12 and the mark 14 at step 41.After statistically processing the amount of the deviations at step 42,and correction-driving the reticle stage at step 43, exposure isperformed at step 44, and the wafer is unloaded at step 45, and adetermination is made if the process is completed for the whole wafer atstep 46, and if the process is not completed for the whole wafer, thenthe processes described above are repeated starting with the wafersetting at step 32.

For example, measurement conditions or measurement parts arepredetermined such that for each mark, switching of light sources suchas a He—Ne laser and a halogen lamp, as the measurement conditions ormeasurement parts, provides respective waveforms of the marks detectedby the CCD camera with good contrast, and a manual switching part isprovided such that the measurement conditions or measurement parts canbe set in the apparatus side.

Second Embodiment

In a second embodiment of the present invention, a TTL mechanism and anOff-Axis mechanism can be switched as measurement conditions ormeasurement parts, and a wavelength filter for varying the centerwavelength of a halogen lamp may be formed as a measurement method.

It is also possible to switch values representing a light intensitydistribution condition of illumination by He—Ne laser light (σ=standarddeviation, not shown) and to change them.

As in the first embodiment, measurement conditions or measurement partsare predetermined such that for each mark, switching of the TTLmechanism and Off-Axis mechanism, switching of center wavelengths of thehalogen lamp, or switching of as, as the measurement conditions ormeasurement parts, provides waveforms for the marks with good contrast,and a manual switching part is provided such that the measurementconditions or measurement parts can be set in the apparatus side. It isalso possible to automatically calculate the contrast and determine foreach mark an optimized measurement condition or measurement part, or awavelength and σ.

In measurement of a wafer position, it is needed to set an optimizedillumination condition since reflection, absorption, scattering,diffraction and interference of the illumination light affect themeasurement of the wafer position depending on the physical features ofthe alignment marks and manufacturing process such as applicationcondition of a resist.

Third Embodiment

In a third embodiment of the present invention, it is possible toautomatically switch measurement conditions for each of the marks formedin the wafer right after starting each lot processing and toautomatically calculate contrast to determine an optimized measurementcondition or measurement part for each mark.

As shown in FIG. 6A, the mark is composed of four rectangular portionshaving the same geometry. As described for the first embodiment, lightflux reflected by the alignment mark transmits the lenses of theprojection optical system 3 through the alignment optical system, andthen forms an alignment mark image WM on the CCD camera.

It is subjected to photo-electric conversion in the CCD camera, thenconverted to a two-dimensional digital sequence in an A/D conversiondevice (not shown). Then, a process window Wp is set for the digitalsignal conversion, as shown in FIGS. 6A and 6B, and the two-dimensionalimage signal is converted to a one-dimensional digital signal sequenceS(x) by an addition process in the y-direction.

The contrast is changed for each mark, as shown in FIGS. 7A and 7B, byswitching the alignment measurement conditions, for example, byswitching light sources such as a halogen lamp or He—Ne laser, or byswitching light intensity distribution conditions σ for He—Ne laserlight. FIG. 7A shows an image signal with high contrast while FIG. 7Bshows an image signal with low contrast.

FIG. 5 is a flowchart showing a process procedure for determining anoptimized measurement condition for each mark.

As shown in FIG. 5, a halogen lamp is selected as the light source atstep 502, and measurement of an alignment mark is performed with theOff-Axis microscope 7 at step 503, and a contrast value is calculated atstep 504.

The measurement and contrast calculation are repeated for the alignmentmarks 11 to 14 at step 505.

Next, the center wavelength of the halogen lamp is varied at step 506,and then a similar measurement of the alignment marks are performed atstep 507. A similar contrast calculation is performed at step 508. Themeasurement and contrast calculation are repeated for the alignmentmarks 11 to 14 at step 509.

Steps 510 to 513 are process steps in the case where He—Ne laser lightis selected as the alignment light source. After the He—Ne laser isselected at step 510, a similar procedure is performed by steps 511 to513, as performed by steps 503 to 505 described above.

Steps 514 to 517 are process steps in the case where a light intensitydistribution a of the He—Ne laser light is varied. After the lightintensity distribution σ is varied at step 514, a similar procedure isperformed by steps 515 to 517, as performed by steps 503 to 505described above.

At step 517, an optimized measurement condition is determined for eachmark from contrast values for varied measurement conditions. Thedetermined measurement condition is held in the lot, and globalalignment is conducted with the determined conditions, for each wafer.

The measurement may be automatically performed for each lot with thedetermined measurement conditions, or the measurement condition may beheld as recipe conditions for each lot. In the case of starting the samelot, the time for the automatic measurement is reduced by referring tothe held measurement conditions.

Embodiment for a Semiconductor Production System

An example of a production system for semiconductor devices (e.g.,semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs,thin film magnetic heads, micro-machines, etc.) by an apparatusaccording to the present invention will be described. In the system,maintenance services such as trouble management or regular maintenance,or provision of software for manufacturing apparatuses installed insemiconductor manufacturing factories are provided by using a computernetwork outside the manufacturing factories.

FIG. 8 is a representation picked up with a certain angle from the wholesystem. In the figure, reference numeral 101 denotes an office of avendor (e.g., an apparatus supplier/manufacturer) providingmanufacturing apparatuses for manufacturing semiconductor devices. It isassumed that the example of manufacturing apparatuses includessemiconductor manufacturing apparatuses for performing various processesused in a semiconductor manufacturing factory, for example, apparatusesfor pre-process (e.g., lithography apparatuses such as exposureapparatuses, resist process apparatuses, and etching apparatuses, heattreatment apparatuses, film deposition apparatuses, planarizationapparatuses, etc.), and apparatuses for post-process (e.g., assemblyapparatuses, inspection apparatuses, etc.). The office 101 comprises ahost management system 108 for providing a maintenance database formanufacturing apparatuses, a plurality of operation terminal computers110, and a local area network (LAN) 109 to construct an intranet or thelike. The host management system 108 comprises a gateway for connectingthe LAN 109 to Internet 105 (external network of the office) and asecurity function to limit access from the outside.

Reference numerals 102 to 104 denote manufacturing factories ofsemiconductor manufacturers as users of the manufacturing apparatuses.The manufacturing factories 102 to 104 may be factories belonging todifferent manufacturers, or may also be factories belonging to a singlemanufacturer (for example, a factory for pre-process and a factory forpost-process). Each of the factories 102 to 103 comprises a plurality ofmanufacturing apparatuses 106, a local area network (LAN) 111 forconnecting them to construct an intranet or the like, and a hostmanagement system 107 as a monitor apparatus for monitoring operationstatus of each manufacturing apparatus 106. The host management system107 provided in each of the factories 102 to 104 comprises a gateway forconnecting LAN 111 in each factory to Internet 105 (external network ofthe factories). This allows access from the LAN 111 via Internet 105 tothe host management system 108 in the vendor 101's side, and thesecurity function in the host management system 108 allows only apredefined user to access it. Specifically, notification from thefactory to the vendor, of status information representing operationstatus of each manufacturing apparatus 106 (for example, symptoms of themanufacturing apparatus with trouble occurrence), as well as receptionfrom the vendor of response information responding to the notification(for example, information indicating management methods for trouble,software and data for the management for the trouble) and maintenanceinformation such as up-to-date software and help information, arepossible. For data communication between each of factories 102 to 104and vendor 101, data communication over LAN 111 in each factory, acommunication protocol (TCP/IP) commonly used in the Internet isemployed. Instead of utilizing the Internet as an external networkoutside the factory, a dedicated line network (such as an ISDN), whichtightens security to avoid access by a third party, may also beutilized. The host management system is not limited to the one providedby the vendor. The user may also construct a database and place it on anexternal network, and to allow access from a plurality of factories ofthe user to the database.

FIG. 9 shows a concept representation picked up with a different anglethan FIG. 8 from the whole system of this embodiment. In the exampledescribed above, the plurality of user factories each havingmanufacturing apparatuses and the management system of the vendor of themanufacturing apparatuses are connected to each other via the externalnetwork, and information about production control of each factory and atleast one manufacturing apparatus is data-communicated via the externalnetwork. On the other hand, in this example, a factory comprisingapparatuses from a plurality of vendors and a management system of thevendor of each of the plurality of manufacturing apparatuses areconnected to each other via an external network outside the factory, andmaintenance information for each manufacturing apparatus isdata-communicated. In the figure, reference numeral 201 denotes amanufacturing factory of a user of manufacturing apparatuses (e.g., asemiconductor device manufacturer), a manufacturing line of which isprovided with manufacturing apparatuses for performing variousprocesses, for example, here, exposure apparatuses 202, resist processapparatuses 203, and a film deposition process apparatus 204. While FIG.9 shows only one manufacturing factory 201, actually, multiple factoriesare connected by a network as well. Each apparatus in the factory isconnected to the others via LAN 206 to constitute an intranet, andoperation management of the manufacturing line is conducted by a hostmanagement system 205.

On the other hand, offices of vendors (e.g., apparatussupplier/manufacturers) such as an exposure apparatus manufacturer 210,a resist process apparatus manufacturer 220, and a film depositionapparatus manufacturer 230, have host management systems 211, 221, and231, respectively, for conducting remote maintenance for the apparatusessupplied by respective manufacturers, and the host management systemscomprise a respective maintenance database and a gateway to an externalnetwork, as described above. The host management system 205 for managingeach apparatus in the user's manufacturing factory is connected via theInternet or a dedicated line network (external network 200) tomanagement systems of a vendor of apparatuses 211, 221, and 231,respectively. In this system, although upon trouble occurrence in any ofthe group of apparatuses in the manufacturing line, the operation of themanufacturing line stops, a quick measure can be implemented byreceiving remote maintenance via the Internet 200 from the vendor of theapparatus with the trouble occurrence, thereby minimizing the stoppageof the manufacturing line.

Each of the manufacturing apparatuses installed in the semiconductormanufacturing factory has a display, a network interface, and a computerfor executing network access software and apparatus operation softwarestored in a storage device. The storage device is such as a built-inmemory, hard-disc, or network file server. The above-described networkaccess software includes web browsers for dedicated or general purposes,and provides on its display a user interface with a picture such as oneillustrated in FIG. 10, for example. An operator who manages themanufacturing apparatuses in each factory, referring to the picture,inputs information such as machine-type of apparatus 401, serial number402, title of trouble 403, day of occurrence 404, degree of emergency405, symptom 406, measure 407, history 408, and so on, into input itemson the picture. The input information is transmitted via the Internet tothe maintenance database, then suitable maintenance information of theresult is sent back from the maintenance database to be presented on thedisplay. The user interface provided by the web browser also implementshyperlink functions 410 to 412, as shown in the figure, thereby allowingthe operator to access more detailed information on each item, toretrieve up-to-date version software to be used for the manufacturingapparatus from a software library provided by the vendor, or to retrievean operation guide (help information), which is provided for factoryoperators to refer to. Here, the maintenance information provided by themaintenance database also includes information related to the presentinvention described above, that is to say, information about suitablemeasurement conditions for each preformed layer and information aboutthe measurement parts or measurement conditions, and the above-describedsoftware library also provides up-to-date software for implementing thepresent invention.

A manufacturing process for manufacturing semiconductor devicesutilizing the production system mentioned above will be described. FIG.11 shows the overall flow of a manufacturing process for thesemiconductor devices. Circuit design for a semiconductor device isconducted at step 1 (circuit design). Masks with the designed circuitpattern formed thereon are fabricated at step 2 (mask fabrication). Onthe other hand, wafers are prepared with a material such as silicon atstep 3 (wafer preparation). Step 4 (wafer process) is referred to as apre-process, and actual circuits are formed on the wafers by lithographytechniques with the prepared masks described above and the wafers. Thenext step, step 5 (assembly), is referred to as a post-process, which isa process to form semiconductor chips by using the wafers fabricated bystep 4, and includes processes for assembly such as assembly processes(dicing, bonding), and a packaging process (chip encapsulation). At step6 (inspection), inspections such as a performance verification test or adurability test for the semiconductor devices fabricated at step 5 arecarried out. The semiconductor devices, through those processes, arecompleted, and then shipped (step 7). The pre-process and post-processare respectively conducted in respective different dedicated factories,and maintenance is performed for each factory by the remote maintenancesystem described above. Information for production control or apparatusmaintenance is also data communicated through the Internet or adedicated line network between the pre-process factory and thepost-process factory.

FIG. 12 shows a detailed flow of the above-described wafer process. Atstep 11 (oxidation), a surface of a wafer is oxidized. At step 12 (CVD),an insulator film is deposited on the wafer surface. At step 13(electrode formation), electrodes are formed on the wafer surface byevaporation. At step 14 (ion implantation), ions are implanted into thewafer. At step 15 (resist process), a photosensitive agent is appliedonto the wafer. At step 16 (exposure), the wafer is printed-exposed withthe circuit pattern on the mask by the above-described exposureapparatus. At step 17 (development), the exposed wafer is developed. Atstep 18 (etching), portions other than the developed resist pattern areetched off. At step 19 (resist strip), a resist after etching, which isno longer necessary, is removed. Multiple circuit patterns are formed onthe wafer by repeating those steps. Since the manufacturing apparatusesused for each process are maintained by the above-described remotemaintenance system, trouble can be prevented beforehand, and whentrouble occurs, performance can quickly be recovered, thereby improvingproductivity for semiconductor devices as compared with conventionalways.

The present invention is not limited to the above embodiments andvarious changes and modifications can be made within the spirit andscope of the present invention. Therefore, to apprise the public of thescope of the present invention the following claims are made.

1. An exposure method of exposing a substrate to a pattern, in which amark in each of a plurality of layers on the substrate is detected foralignment of the substrate, said method comprising steps of:illuminating a mark in each of a plurality of layers on a substrate;detecting an image of the illuminated mark in each of the plurality oflayers; and setting an illumination condition in said illuminating stepfor the mark in each of the plurality of layers, wherein, in saidsetting step, the illumination condition is set based on a manualindication.
 2. A method according to claim 1, wherein the manualindication is performed through a manual switching part.
 3. An exposuremethod of exposing a substrate to a pattern, in which a mark in each ofa plurality of layers on the substrate is detected for alignment of thesubstrate, said method comprising steps of: illuminating a mark in eachof a plurality of layers on a substrate; detecting an image of theilluminated mark in each of the plurality of layers; and setting anillumination condition in said illuminating step for the mark in each ofthe plurality of layers, wherein the illumination condition is set basedon the detected image.
 4. A method according to claim 3, wherein theimage of the illuminated mark in each of the plurality of layers isdetected in each of a plurality of illumination conditions, and theillumination condition is set for the mark in each of the plurality oflayers based on the detected images.
 5. A method according to claim 4,wherein the illumination condition is set for the mark in each of theplurality of layers based on a contrast of each of the detected images.6. A method according to claim 4, wherein the setting is performed foreach of a plurality of substrates.
 7. An exposure apparatus for exposinga substrate to a pattern, said apparatus detecting a mark in each of aplurality of layers on the substrate for alignment between the substrateand the pattern, said apparatus comprising: a detection system whichilluminates a mark on the substrate and detects an image of theilluminated mark; and a setting system which sets an illuminationcondition of said detection system for a plurality of marks, used foralignment, on the substrate, with respect to each of the plurality oflayers, wherein said setting system sets the illumination conditionbased on a manual indication.
 8. An apparatus according to claim 7,wherein said setting system includes a manual switching part.